Thermoelectric (TE) technology has attracted worldwide interest in recent years. TE devices can be used for cooling and electrical power generation purposes in a variety of applications. While much of the work in thermoelectric technology has focused on the development of new thermoelectric materials, incorporation of the newly-developed materials into TE devices and practical application of the TE devices in automotive and other applications is also being investigated.
Batteries, including those used in automotive applications, are characterized by optimum operational temperature windows. During operation, high battery temperatures due to consecutive charge-discharge cycles, hot weather, engine heat, etc., are common. This results in a short battery lifespan and degraded battery performance. On the other hand, low battery temperatures encountered during cold startup conditions in cold weather, for example, prohibit efficient battery operation due to increased internal electrical resistance.
Thermoelectric technology includes heating and cooling capabilities of TE devices. The basis of such heating and cooling capabilities is the Peltier effect, which is expressed using a Peltier circuit. A Peltier circuit is a TE device which includes two thermally-opposite sides. When an electrical current is applied to the Peltier circuit in one direction, one side of the TE device creates heat, and therefore, has heating capability while the other side absorbs heat, and therefore, has cooling capability. Reversing the polarity of the electrical current applied to the Peltier circuit creates the opposite effect.
Accordingly, a control scheme or method is needed which utilizes a TE device to cool or heat a battery, as required, using the Peltier effect.